(a) Field of the Invention
The present invention relates to a method for communication of a base station, a terminal, and a relay station.
(b) Description of the Related Art
In the event of a disaster or calamity, important social infrastructure may be destroyed or damaged. Some of the important social infrastructure includes a variety of communication facilities such as wireless phones, wired phones, internet networks, etc. Destruction or damage of such communication facilities would increase social chaos following a disaster and make it difficult to have a society's ability to recover from the disaster. Therefore, it is crucial to provide high-reliability support for means to quickly recover or replace the communication facilities. For high-reliability support, a mobile communication system (HR-Network) should satisfy the following requirements.
First, it should have backward compatibility with an existing system, i.e., WirelessMAN-OFDMA or WirelessMAN-Advanced Interface. Next, it should be capable of multimode operation which enables an HR-base station 100, an HR-mobile station HR-MS, and an HR-relay station HR-RS to play the roles of other stations as well as their own roles.
Moreover, communication should be sustained even if a base station, a relay station, or a wireless link is disabled, that is, in the event of a single point of failure (SPOF). Also, it is necessary that direct communication is possible between different terminals. Multicast transmission, i.e., enhanced multicast communication, needs to be provided within a network, and path management needs to be provided to manage routing and forwarding for data transmission and reception.
Particularly, when a terminal wants to transmit data to another terminal within a base station or relay station through the base station or relay station, delay may be generated because routing and services should be done at the base station or relay station through an upper layer network.
Moreover, it is necessary to provide continuing support to communication between terminals in case of non-smooth communication due to collapse of a backbone network of the base station.